Based on observations made on animal models of anthracycline cardiotoxicity, as studied in our unit, a review was made of gross anatomic, histologic and ultrastructural changes induced in experimental animals by the administration of antineoplastic agents of the anthracycline group. Emphasis was given to studies involving dose schedules resulting in cardiac (myofibrillar loss, dilatation of sarcoplasmic reticulum, myocyte necrosis and interstitial fibrosis) and extracardiac (bone marrow depression, gastrointestinal toxicity, nephrotoxicity) lesions, and to certain features (involvement of the pericardium or of the cardiac conduction system) that tend to show a predisposition to occur in a given species. The basic features of the cardiac lesions, i.e., dilatation of sarcoplasmic reticulum and myofibrillar loss tend to have a similar occurrence in all species; myocyte necrosis tends to develop only when high doses of anthracyclines are used. The beagle dog is recommended as a large animal model because it yields highly reproducible results.